Electronic discharge tube with a plurality of plate-grid systems



March 1952 L. w KOEHLER 2,539,397

ELECTRONIC DISCHARGE TUBE WITH A PLURALITY OF PLATE-GRID SYSTEMS FiledOct. 3, 1949 IN VEN TOR.

Louis W. Kaeh/er u g a Patented Mar. 18, 1952 UNITED STATES PATENTOFFICE ELECTRONIC DISCHARGE TUBE WITH A PLURALITY F PLATE-GRID SYSTEMS 6Claim.

This invention relates to electronic discharge tubes of the typecontrolling the flow of electronsby means of a plurality of plate-gridsystems and it has for itsmain object to provide an electronic dischargetube of great sensitivity, capable of producing high amplification gainsin which the control energy used at the control grids for controllingthe current flow to the plate or plates is smaller than that required incustomary tubes with grid control of a comparable con struction.

A further object of the invention consists in providing an electronictube with a plurality of plate and grid systems which may be connectedwith points of an oscillation carrying system showing opposite phaserelation which is capable ofutilizing the joint and added actionofopposite voltage fluctuations.

A further object of the invention consists in providing an electrondischarge tube with a plurality of plate-grid systems which areessentially independent of each other but which may be connected withpoints of an oscillation carrying system showing opposite phase relationand in which the control of the current flow isexercised continuouslybythe joint action of the said opposite phases acting on the grids of theplategrid systems, the grids of the independent systems cooperating tocontrol the current flow from the cathode to the plates of all systems.

A further object of the invention consists in providing an electronicdischarge tube with a plurality of plate-grid systems in whichthe.control of the current flow is produced by a combinedelectronaccelerating and retarding action of the grid and by a deflection of theelectron flow, thus combining the advantages of these two methods ofelectron control.

A further object of the invention consists in providing an electronicdischarge tube with a cathode and a plurality of plate-grid systems inwhich the electron stream produced by the cathodesweeps from oneplate-grid system to another system under the joint influence of thegrids of all systems while the said electron stream is'controlled inevery moment by the change of voltage of the grids which it passes;

To attain these objects an electronicdischarge tube provided with aplurality of symmetrically arranged plate-grid systems is used accordingto the invention in which a cathode or cathodes emit an electron streamalong the plane of symmetry of said systems when not deflected by thesame, while each plate-grid system consists oi or comprises sectionsinclined towards the direction in which the electron stream is emitted;which sections therefore are reached by the flow of electrons as soon assaid flow is defleotedby the grid charges. The electronfiowthusdefi'ected which passes through one of the grids of one systemis then also acted upon by' the charge of the grids which it passes sothat a double action results, one of the actions being the customarygrid action accelerating and decelerating the flow of electrons, whilethe second action is a result of the deflection of the electron flowfrom its original direction whichnormally does not intersect one of thegrids ofthe systems. The influence of the grid charge is thus increasedso that less energy is necessary to produce the same change of platecurrent.

Preferably according to the invention, the arrangement is symmetrical intwo directions and consists of plate-grid systems arranged on both sidesof'a cathode which are either composed of'two sections which areinclined towards each other and towards the plane of symmetry of thesystems or which are curved or bent towards said plane or symmetry. Theelectron flow emitted by the cathode. on both sides oitne' same isinfluenced in the same way and deflected towards the same side, thusproducing a con tinuous deflection of the entire emission of the cathodewith the result that the electron; flow 01' the cathode passes throughthe grid whichhas a voltage deflecting it in its direction. Theeutireelectron stream emitted by the cathode". will then be controlled bythevoltage' appliedto the grid, once the stream has been. deflected in:its direction.

According: to the inventlonmoreover this action may be improvedby'connecting' the grids of the plate-grid systems withpoints ofan-oscililation carrying system which are permanently in opposite phaseso that both grids act in op posite manner and may simultaneouslycontribute to the deflection of the electron stream in the samedirection. In this'way a. well integrated multiple action may beexercised on. the electron stream, driving said electron stream towardsthe grid of one or the other system by the joint action of the gridswhile. the" stream thus passing the grid is controlledby the veil:- ageapplied to the grids.

This" action may be assisted. according to the invention, by providingthe'cathode withflow-directing wings or shields preventing emission incertain directions and directing the electron flow in such a manner thatit will have the tendency to stream substantiallyin theplane of symmetry3 passing between the plate-grid systems grouped on both sides of acathode.

Further, according to the invention, the electronic discharge tube maybe connected with the oscillation carrying system in the manner of twotubes connected in push-pull connection whereby a great simplificationis frequently obtainable.

Further characteristic features and objects of the invention will beapparent from the following detailed specification.

The invention is illustrated in the accompanying drawings showing oneembodiment of the invention and one modification thereof. It is howeverto be understood that the drawings illustrates an embodiment of theinvention merely by way of example, selected in order to be able toexplain the principle of invention and the best mode of applying saidprinciple. Modifications of the invention not illustrated in the drawingare therefore not necessarily departures from the essence of theinvention.

In the drawing:

., Figure 1 is a diagram illustrating an electronic discharge tube andthe connections of the same by way of example.

Figure 2 is a perspective view of the electronic tube with the glassenvelope broken away.

Figure 3 is an exploded perspective view of the cathode plate and grid,a modification of the plate illustrated in Figure 1 being shown.

Figure 4 is a series of three diagrams showing the flow of electrons inthree different stages of the operation.

As has been explained above the principle of the invention consists inproviding an arrangement in which the electron stream emanating from thecathode will be subjected simultaneously to deflection and to theaccelerating and decelerating action of one of the grids of one of thesystems. The deflection towards different plate-grid systems is producedby the grid voltage prevailing at the moment and the invention istherefore most useful in circuits in which the grid voltages applied toall the plate-grid systems may cooperate to produce a deflection towardsone and the same plate-grid system. Such an arrangement is shown inFigure l of the drawings as will be explained below.

The construction of the electronic discharge tube is illustrated by wayof example in Figures 2 and 3. The discharge tube comprises a cathode 5which may be either a directly or indirectly heated cathode, the lattertype being shown in Figures 2 and 3. The heater 6 is arranged in theinterior of a cathode tube Ill which is preferably provided withelectron flow directing side wings i I having the shape of straight orslightly curved strips welded to the cathode tube L The flow directingwings or strips are provided on those sides of the cathode tube l0 whichare turned towards the plate-grid systems and their purpose is toconcentrate the electron stream between them so that the electrons willbe mainly emitted from those portions of the cathode tube which iscontained between the wings, the general direction of the emittedelectron stream. when not deflected. being the plane of symmetry passingbetween the systems.

The discharge tube 9 comprises at least'two symmetrically arrangedplate-grid systems I, 8 each system consisting of two plates or twoplate sections l5, l6, and I1, I8 respectively inclined towards eachother and towards the plane of symmetry between the systems. The twoplate sections l5, l6 and H, l8 thus form a roof shaped plate, the roofshaped plates of the two systems facing each other across the cathodewith their concave sides turned towards each other. The cathode I0 isthus enclosed within a rhomboidal space formed by the two plates.

Instead of roof shaped plates as shown polygonal or curved plates may beused turning their hollow or concave sides towards the cathode andenclosing the same. The exact shape of the plates is not materialprovided the distance between the plates in the median plane passingthrough the plate centers is always larger than the distance between theouter edges of the plates.

The grids I9, 20 have substantially the same shape although theinclination of the lateral sections towards each other may slightlydiffer from that of the plates. In the central portion facing the flowdirecting wings ll of the cathode H) the grid may be replaced by shields2i or imperforate frame portions as there is no electron flow throughthis section. As shown in Figure 3 the grid may therefore consist of aframe 23 the side portions of which are joined by transverse members atthe end and by shields 2| in the middle. The customary fine wires 24 arestretched between the lateral portions of the frame in the customarymanner.

In Figures 2 and 3 a modification of the shape of the plate is shown. Aswill be seen especially in Figure 3 the plate may be provided withserrations 25, the cross section of the serrated portions beingapproximately of saw tooth form. The front or stepped portion of eachsaw tooth separating two consecutive serrations may be arrangedapproximately in the direction in which the electron stream flows sothat mainly the inclined parts of the serrated plate collect electrons.The surface of the plate is thus enlarged without producing pockets orother flow impeding disturbances.

As will be seen from Figure 3 each plate and each grid is connected to aseparate lead in wire which may or may not be connected with the plugsof the socket and the same holds good of each grid I9, 20. The grids areconnected with separate lead in wires 29a. and 30a at the top while theplates are joined to the wires 28, 38. In addition lead in wires 26, 21for the cathode and further lead in wires 29, 30 for the heater areshown in the figure. The tube socket according to the invention istherefore provided with five plugs in addition to the connections whichare provided for the grid systems.

The tube may be connected in various ways one of the methods ofconnecting the tubes being shown in Figure 1.

In the diagram the two grids 19, 2|! are connected with a condenser 30of an oscillation circuit 3| which includes coil 32 which maybeinductively or otherwise connected to any oscillation carrying systemsuch as an antenna 33. Moreover the two plate systems I, B are connectedwith the output coil 35 shown as one of the coils of a high frequencytransformer 36 leading to a system capable of utilizing the amplifiedoscillations such as a receiver. The cathode l0 may be connected withground G over a suitable resistance or filter and with conductor 39leading to the centers of the center tapped coils 32, 35.

The operation will be readily understood when referring to the diagramsshown in Figure v4. During the amplification of a full wave let it beassumed that grid i9 is negative and grid 20 is positive during thefirst half wave. It will then be clear that theelectron stream comingout of the central portion of the cathode between the flow directingwings. H is deflected towards. the positive grid 20 and will be taken upby the positive plate 8, the negative grid [9 actually assisting in thisdeflection. When the positive wave will have reached its peak theelectron flow will be that shown in Figure in.

As the positive voltage decreases theelectron stream turns towards themiddle and when the oscillating voltage passes the zero point it will beapproximately parallel to the median plane.

passing between the two plate-grid systems. This phase is shown inFigure 4b. During the follow-- ing negative phase the grid 20 willbecome negative while grid I9 receives the positive voltage with theresult that the electron stream will now be deflected towards the plateI as indicated in Figure 4c.

The discharge tube according to the invention therefore operates in themanner of a push-pull arrangement, but with the difference that the twoplate and grid systems always cooperate in shifting the electron systemfrom one plate system to another.

An increase in sensitivity and an increase in the amplification factortherefore results from the fact that the electron stream is not onlysubjected to the retarding and accelerating influence of the grid butalso sweeps along the grid from one system to the other system. Theelectron stream is thus subjected to a double control action one ofthese control actions being performed by" the cooperation of the twosystems. This materially improves the characteristics of the tube andmoreover less energy on the grid is required to effect the control ofthe'electron flow in the tube.

The tube thus allows to combine the advantages of direct grid controlwith the many advantages of the control by deflection.

The tube may be used in all arrangements in which a high degree ofamplification or sensitivity is required but also in many otherarrangements especially in those which require the use of a push-pullconnection. Moreover the tube may replace the customary tubes in manyarrangements in which a dual or push-pull connection may be ofadvantage, radio frequency amplifiers, detectors, audio frequencyamplifiers, oscillators, modulators, etc., being mentioned as examples.

It will be clear that the construction of the details of the electronicdischarge tube and also the shape of the parts described is in manyrespects not essential for the realization of the principle of theinvention and therefore changes of an unessential nature will not affectthe essence of the invention as defined by the annexed claims.

Having described the invention, what is claimed as new is:

1. An electronic discharge tube comprising an evacuated container, anelectron emitting cathode, two anode-grid systems located symmetricallyon both sides of a plane of symmetry passing through the cathode, eachsystem including an anode and a grid, the latter covering andintersecting completely the space between the anodes, and each anode andgrid consisting of two sections, inclined towards each other and towardsthe said plane of symmetry, electron flow preventing shields on thecathode arranged substantially on both sides of a plane at right anglesto the said plane of symmetry, said shield dividing the electron flowemitted by the cathode and confining it to a zone located in thevicinity of the aforesaidpiane of symmetry, and means for. impressing;fluctuating voltages of diiferentphase on the grids of said system.

2. An electronic discharge tube comprising an evacuated container, anelongated electron emitting, cathode, two anode-grid systems, locatedsymmetrically on both sides of a plane of symmetry passing through thecathode, each system including an anode and a grid, the latter coveringand intersecting completely the space between the two anodes of the twosystems, and each anode and grid of each system consisting of sectionsinclined towards each other and inclined towards the plane of symmetry,the two anodes and grids of the two systems facing each other acrossagap, bisected by the plane of symmetry, shields on the cathode on bothsides of a plane at right angles to the aforesaid plane of symmetry,said shields being adapted to prevent a new of electrons in thedirection of the said last named plane, thus dividing the flow ofelectrons from the cathode to the two anode sections into two separatebundles, and means for impressing fluctuating. voltages of oppositephase on the grids of the anode-grid systems, the fluctuatin gridvoltages producing a shifting of the electron flow oi the cathodetowards one of the systems in accordance with thefluctuations, the gridsof the systems towards which the electron flow has been deflected.controlling the electron flow towards the anode of the system.

3. An electronic discharge'tube comprisingan evacuated container, anelongated electron emitting cathode; two anode-grid systems locatedsymmetrically on both sides of a plane of symmetry passing; throughthecathode, each anode and grid of each anode-grid system consisting oftwo. sections. inclined towards each other and inclined towards theaforesaid plane of symmetry, and arranged symmetrically with respect toa second plane of symmetry at right angles to the aforesaid plane ofsymmetry, each grid covering and intersecting completely the spacebetween the anode and cathode, the outer end of said grid and anodesections being separated by a gap bisected by the first named plane ofsymmetry, shields on said cathode intersecting the second plane ofsymmetry, said shields being adapted to prevent an electron flow in thedirection of the said second plane of symmetry, thus dividing theelectron flow from the cathode to the anode of each system, means forimpressing fluctuating voltages of different phase on the grids of thegrid systems, the fluctuating grid voltages of different phasedeflecting the electron flow towards one of the systems, the grid ofwhich controls the deflected electron flow towards the anode of thesystem.

4. An electronic discharge tube comprising an evacuated container, anelectron emitting cathode, two anode-grid systems, substantiallyencompassing said cathode and located symmetrically on both sides of aplane of symmetry passing through said cathode, each plate and each gridof the anode-grid systems consisting of two sections inclined towardseach other and inclined towards the above mentioned plane of symmetry,the outer ends of said sections facing each other across a gap bisectedby the aforesaid plane of symmetry, the two sections of each anode andeach grid of the anode-grid system being symmetrically arranged withrespect to a second plane of symmetry arranged at right angles withrespect to the first mentioned plane of symmetry, shields on the saidcathode on the sides of the cathode facing the anode-grid systems, saidshields being adapted to prevent a flow of electrons between the cathodeand the anode-grid system in a zone near the said second plane ofsymmetry, thus producing a divided flow of electrons between the cathodeand the anode sections in zones located in and on both sides of thefirst mentioned plane of symmetry, means for impressing fluctuatingvoltages of opposite phase on the two grids of the two anodegridsystems, the combined influence of the two grids, when equal, producingan electron flow substantially parallel to the first named plane ofsymmetry and when unequal producing an electron flow directed towardsthe anode sections of one of the anode-grid systems, said flow passingthrough one of the grid sections of said system.

5. An electronic discharge tube comprising an evacuated container, anelongated electron emitting cathode, two anode-grid systems, arranged insubstantial parallelism to the said cathode and g substantiallyencompassing the same, each anodegrid system being located symmetricallyon both sides of a plane of symmetry passing through said cathode, eachanode and rid of the anodegrid system consisting of two sections,inclined towards each other and inclined towards the above mentionedline of symmetry, the outer ends of said sections facing each otheracross a gap bisected by the aforesaid plane of symmetry, the twosections of each anode-grid system being symmetrically arranged withrespect to a second plane of symmetry at right angles to the firstmentioned plane of symmetry, and each anode section being fully coveredby a substantially parallel section of the grid on the side facing thecathode, shields on both sides of the cathode facing the point ofjunction of the sections of the plates and grids of the anode-gridsystems. said shields being arranged on both sides of the first namedalternatively suppressing and producing a current flow between thecathode and the anode of one of the systems, the electron flow from thecathode thus being divided into two distinct bundles, oscillating aroundthe first named plane of symmetry, the extent of said oscillations beinglimited by the inclination of the anode-grid system toward the firstnamed plane of symmetry.

6. An electronic device as claimed in claim 5, in which the grids areprovided with imperforate strips facing the shields oi the cathode.

LOUIS W. KOEHLER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,437,607 Mueller Dec. 5, 19221,632,104 Whiting June 14, 1927 1,672,977 Field June 12, 1928 2,061,594Samuel Nov. 24, 1936 2,295,816 Wilson Sept. 15, 1942 FOREIGN PATENTSNumber Country Date France 1 Nov. 13, 1923

